Flapper lock open apparatus

ABSTRACT

Various techniques for holding open an SSSV using expansion technology are disclosed. A sleeve is delivered to the SSSV and expanded mechanically or hydraulically to deposit the deformed sleeve in position over a flapper or against a flow tube holding the flapper in the open position.

FIELD OF THE INVENTION

[0001] The field of this invention is mechanisms that can hold open asubsurface safety valve (SSSV) that has malfunctioned so that anothervalve can be installed to take its place.

BACKGROUND OF THE INVENTION

[0002] SSSVs are normally closed valves that are used primarily inoffshore and gas wells to prevent uncontrollable flow of fluid to thesurface, in the event the surface safety equipment fails to properlyoperate. If the SSSV malfunctions or for any other reason requiresreplacement with a backup SSSV, the well operator will normally want theold SSSV locked in the open position so it does not interfere with welloperations after the old SSV has been taken out of service. Typically,to avoid undue complication in the design and operation of an SSSV, thelock open assembly is not installed with the SSSV but is subsequentlyrun in when needed on an accessory tool known as a flapper lock open(FLO) tool.

[0003] One known design of an FLO tool is U.S. Pat. No. 4,577,694, whichillustrates the use of a scroll of wound spring steel that is allowed tospring out after being delivered to the SSSV to keep the flapper fromrotating back to a closed position. The downside of this design andseveral others is that flow through the locked open SSSV could and did,at times, dislodge the lock open device, allowing the flapper to closeoff the well. In this particular patent, the ring of steel was coiled,like a watch spring and held at opposite ends until properly positioned.When the delivery tool released the ring, it sprang outwardly to contactthe flapper. This tool was complicated and required stocking of varioussizes of rings as well as an installation method that involved twowireline trips with jar down/jar up activation.

[0004] Another technique, shown in U.S. Pat. No. 5,574,889 required thatthe flow tube be engaged and forcibly moved down to get the flapper intothe open position. After that one or more indentations were made in theflow tube, which could engage a shoulder and prevent the flow tube fromreturning to the flapper-closed position. This device had severaldisadvantages. The flow tube was permanently damaged. The tool requiredenough force to overcome bias on the flow tube to push it into theflapper open position. Finally, part of the procedure required pumpingfluid under pressure into the well, which could adversely affectsubsequent production.

[0005] Another technique, shown in U.S. Pat. No. 5,564,675, the flowtube is forcibly engaged and pushed so far down that the actuatingpiston comes out of its seal bore in a manner as to wedge the flow tubein the flapper open position. This design has similar disadvantages asU.S. Pat. No. 5,574,889 and a further disadvantage that flowcommunication to the control system occurs due to operation of this lockopen device.

[0006] Another technique illustrated in U.S. Pat. No. 6,059,041, forcesthe flow tube down and releases an expandable tube to hold the flapperopen. Similar, disadvantages as the previous two techniques are realizedin this design.

[0007] Other art in the area of lock open devices for SSSVs includesU.S. Pat. Nos. 3,786,866; 4,344,602; 4,967,845; 4,624,315 and 4,457,379.Of more general interest are U.S. Pat. Nos. 5,040,283 (using a shapememory metal for downhole patches); 4,846,281; 4,760,879; 4,729,432;4,566,541 and 4,213,508.

[0008] One of the objectives of the present invention is to deliver andset a hold open device in an SSSV in a manner that it will not becomedislodged. The technique to accomplish this objective comprises using anexpansion of a tubular member so as to deform it into position where itwill prevent a flow tube from returning to the flapper closed positionor to actually use the expanded structure directly against the flapperwhen it is held open by the flow tube. Those skilled in the art willhave a clearer understanding of the various embodiments foraccomplishing the objective of holding an SSSV in an open position fromthe detailed description of the preferred embodiment and the claims,which appear below.

SUMMARY OF THE INVENTION

[0009] Various techniques for holding open an SSSV using expansiontechnology are disclosed. A sleeve is delivered to the SSSV and expandedmechanically or hydraulically to deposit the deformed sleeve in positionover a flapper or against a flow tube holding the flapper in the openposition.

DETAILED DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a perspective view of a slotted sleeve in the unexpandedposition;

[0011]FIG. 2 is the view of FIG. 1 with the sleeve in the expandedposition;

[0012]FIG. 3 is an alternative sleeve having longitudinal flutes beforeexpansion;

[0013]FIG. 4 is the sleeve of FIG. 3 after expansion;

[0014] FIGS. 5-8 are an expansion sequence for a sleeve using amechanically compressed resilient sleeve to accomplish the expansion.

[0015] FIGS. 9-12 show an expansion sequence for a sleeve using aninflatable;

[0016] FIGS. 13-16 show an expansion sequence of a sleeve against aflapper using a mechanically compressed resilient ring.

[0017] FIGS. 17-18 show the use of a ring with extending collet fingersthat is run in and outwardly expanded to hold a flow tube against theflapper in the open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] The present invention deals with ways of holding an SSSV in anopen position. This can be done by holding open the flapper, asillustrated in FIGS. 13-15 or holding the flow tube when the flow tubepushes the flapper into an open position, as shown in FIGS. 5-8, forexample.

[0019] The preferred device for holding the SSSV open is a tube 10 thathas slots 12 or any other shaped openings on it to facilitate expansionbut at the same time to retain sufficient structural integrity afterexpansion to avoid collapse or simple breakage. Shown in FIG. 1, theslots 12 are rectangular and are in alignment with the longitudinal axisof the tube 10. Other arrangements and orientations are envisioned. Asshown in FIG. 2, the slots 12 turn from a rectangular shape to a diamondshape after expansion. The tube 10 is permanently deformed so that itwill not spring back to its run in dimension. The deformation results ina residual holding force to keep the tube 10 in place against thevelocity of flowing fluid. The expansion can be carried out using avariety of techniques such as a swage, a mechanically compressedresilient sleeve, or an inflatable, to mention a few possibilities.

[0020]FIG. 3 shows a tube 14 having longitudinal folds or corrugations16 to give it a small enough diameter to allow it to be positionedproperly inside the SSV. In the expanded position it is rounded andpreferably deformed into contact with a flapper or the flow tube or bothto hold the SSSV in the closed position. Once again, many expansiontechniques can be used to fixate tube 14 in the chosen position.

[0021] FIGS. 5-8 show the flow tube 18 in SSSV housing 20 in theposition where the flapper (not shown) is in the open position. The tube22 is delivered on an expansion tool 24. It has a body 26 and a shiftingsleeve 28 that bears down on ratchet sleeve 30 to compress the resilientring 32. The set position can be retained with lock ring 34 by virtue ofteeth 36. Those skilled in the art will realize that FIGS. 5-8 areschematic. Locking the set position is not essential. The tube 22,however constructed, is to be expanded sufficiently to plasticallydeform or expanded in such a way as to leave a residual compressiveforce in the grooves such as 38 and 40 into which it anchors bydeforming to take their shape, as shown in FIG. 7. The compressive forceapplied to the resilient ring 32 has been removed in FIG. 8 so that thetool 24 can be withdrawn after the resilient ring 32 relaxes. Tube 22can be expanded into a single groove or two grooves or any other surfaceirregularity internal to the SSSV where the flow tube 18 will be in theflapper open position. The tube 22 can even be expanded into a smoothbore inside the SSSV to trap the flow tube 18, although a surfaceirregularity is preferred for better anchoring of the tube 22.

[0022] FIGS. 9-12 show the use of an inflatable tool 42, which isschematically illustrated. It has an inflatable element 44 and a valvesystem 46 of a type commonly used in inflatable packers. The valvesystem 46 comprises a check valve 48 to hold element 44 in the inflatedposition. A release valve 50 overrides check valve 48 to release theinflation pressure. A passage 52 communicates the inflation pressure tounder the element 44. The tube 22 is expanded and preferably anchored toan internal surface irregularity after being plastically deformed. Theflow tube 18 is again locked into position with the flapper open.

[0023] FIGS. 13-16 are similar to FIGS. 5-8 except for the locationwhere the tube 22 is being expanded. In FIGS. 13-16, the tube 22 isexpanded against the flapper 54 itself. The tube 22 straddles theflapper 54 and engages shoulders 56 and 58. Those skilled in the artwill appreciate that variation of the length of tube 22 can allow it tobe expanded against the edge of the flow tube 18 or straddling theflapper 54 or spanning over one or both of these SSSV components.

[0024] FIGS. 17-18 display another technique. Here a ring 60 hasextending fingers 62 that have heads 64 at their ends. A running tool(not shown) delivers a wedge ring 66 that pushes the heads 64 onto ashoulder 68 or some other surface irregularity so that the entireassembly is anchored. Depending on the placement, the assembly candirectly retain a flapper 54 or a flow tube 18 with the flapper 54 inthe open position or parts of both. In this application the fingers 62are not necessarily plastically deformed with respect to the ring 60.Rather, the preferred technique is a wedging action to retain theassembly in place to hold the flow tube 18 the flapper 54 or both in theflapper-open position.

[0025] Those skilled in the art will appreciate that the use of a sleevethat is expanded to a degree to leave a residual contact force allowsfor a greater assurance that the sleeve will stay in place after it hasbeen set. The sleeve placement can be such that it retains the flapperdirectly or indirectly through the flow tube, which actuates it. Thesleeve can be perforated with openings of various shapes or a commonshape. The openings can be arranged in an orderly pattern or can berandomly distributed. The sleeve can also be solid without any openingsand its thickness can be constant along its length or it can be varied.The expansion and run in device can be a swage, a mechanically expandedresilient or other type of sleeve or an inflatable. Known tools can beused to perform the expansion or they can be slightly modified to meetthe requirements of the particular application. Such tools can contactthe flow tube 18 to put it into the open position, or they can gothrough the flow tube and push the flapper 54 into the open positionbefore actuation. For example, a mechanically set packer can be usedwithout the slip assembly and even without the locking mechanism thattypically holds the set. This is because the sleeve, once expanded,needs not to be held in that position. Once the expansion isaccomplished the expansion tool can be promptly removed. Regardless ofthe expansion technique, any type of sleeve mentioned above ormodifications of such sleeve can be used to effectively hold the SSSV inthe open position.

We claim:
 1. A method for locking open a subsurface safety valve (SSSV),comprising: delivering a ring into the SSSV; putting the SSSV into anopen position; and expanding said ring with an applied force to secureits placement while holding the SSSV open.
 2. The method of claim 1,comprising: plastically expanding said ring.
 3. The method of claim 1,comprising: engaging a shoulder in the SSSV with said expanded ring toimprove fixation.
 4. The method of claim 1,comprising: providingopenings in said ring.
 5. The method of claim 1, comprising: engagingthe flapper with said ring.
 6. The method of claim 1, comprising:engaging the flow tube with said ring.
 7. The method of claim 5,comprising: engaging the flow tube with said ring.
 8. The method ofclaim 4, comprising: providing elongated slots as said openings.
 9. Themethod of claim 1, comprising: driving a swage into said ring to expandit; and removing the swage.
 10. The method of claim 1, comprising:providing a plurality of collet fingers extending from said ring andterminating in a head; wedging said heads in the SSSV to secure the openposition.
 11. The method of claim 10, comprising: using a ring shapedswage to wedge said heads; and leaving said swage in place after saidheads are wedged.
 12. The method of claim 1, comprising: mounting saidsleeve on a resilient member in an actuating tool; applying acompressive force to said resilient member; and forcing the sleeve toexpand with said resilient member.
 13. The method of claim 1,comprising: expanding said sleeve with an inflatable tool.
 14. Themethod of claim 1, comprising: providing longitudinal corrugations insaid ring to reduce its outer dimension for placement; and expandingsaid ring to remove said corrugations.
 15. The method of claim 14,comprising: expanding said ring to beyond removal of said corrugations.16. The method of claim 2, comprising: engaging a shoulder in the SSSVwith said expanded ring to improve fixation.
 17. The method of claim16,comprising: providing openings in said ring.
 18. The method of claim17, comprising: driving a swage into said ring to expand it; andremoving the swage.
 19. The method of claim 17, comprising: mountingsaid sleeve on a resilient member in an actuating tool; applying acompressive force to said resilient member; and forcing the sleeve toexpand with said resilient member.
 20. The method of claim 17,comprising: expanding said sleeve with an inflatable tool.